Federal agents wearing hazardous material suits and breathing apparatus inspect the trash can outside the West Hills Subdivision house of Paul Kevin Curtis in Corinth, Miss. Curtis is in custody under the suspicion of sending letters covered in ricin to the U.S. President Barack Obama and U.S. Sen. Roger Wicker, R-Miss. (ASSOCIATED PRESS / Rogelio V. Solis)

OXFORD, Miss. (AP) — Federal authorities have produced scant evidence linking a Mississippi man to the mailing of ricin-laced letters to the president and a senator, his attorney says.

Christi McCoy said after a court hearing Friday that the government has offered no evidence to prove her client, Paul Kevin Curtis, had possession of any ricin or the seed from which it is extracted — castor beans. An FBI agent testified during the hearing that he could not say if investigators had found ricin at Curtis’ home, and McCoy said the evidence linking the 45-year-old to the crime so far has hinged on his writings posted online.

He is adamant that he did not do this, and she said she has seen nothing to prove him wrong.

Curtis was ushered into the courtroom before the hearing began in an orange jail jumpsuit and shackles. He turned to face his daughter in the audience before the hearing and whispered, “I didn’t do it.”

Prosecutors had wanted to delay the hearing because searches of Curtis home and car had not been completed and DNA and other tests are pending.

FBI spokeswoman Deborah Madden said Saturday that she couldn’t discuss what was found during the search of Curtis’ home because it’s part of an ongoing investigation.

Curtis’ brother Jack Curtis and 20-year-old daughter Madison Curtis watched the court proceeding Friday and said afterward they are not convinced he did what he is accused of, even though they tried to keep an open mind about what would be presented.

“After hearing what I heard in this courtroom, it appears to me that the reason I haven’t been provided any evidence is there appears to be none that would link my brother directly to the charges that have been made,” Jack Curtis said after the hearing.

So far, Paul Kevin Curtis is the primary focus for investigators and the only person arrested in connection with sending those letters and a third threatening letter mailed to a judge. But during a hearing Friday, FBI agent Brandon M. Grant testified that authorities were still trying to determine whether there were any co-conspirators.

As the hearing went on for roughly two hours, Grant said under questioning by Curtis’ attorney that he could not say whether any ricin had been found at Curtis’ home because the investigation was ongoing. Investigators had found a package they were interested in, but Grant said he did not know what was in it.

Grant testified that there were indentations on the letters from where someone had written on another envelope that had been on top of them in a stack. The indentations were analyzed under a light source and turned out to be for Curtis’ former addresses in Booneville and Tupelo, Grant said.

Grant also testified that there was one fingerprint on the letter sent to the judge but that it didn’t match Curtis. He said several people handled the letter, and DNA and other tests are pending.

Curtis’ lawyer peppered the agent with questions in an attempt to show the government had little hard evidence, but Grant said people’s lives were at risk and it wasn’t like a fraud investigation in which authorities could gather more evidence before making an arrest.

Family and acquaintances have described Curtis as a caring father and enthusiastic musician who struggled for years with mental illness and who was consumed by trying to publicize his claims of a conspiracy to sell body parts on the black market.

Curtis is an Elvis impersonator and performed at parties. Friends and relatives also say he spiraled into emotional turmoil trying to get attention for his claims of uncovering a conspiracy to sell body parts on the black market.

Grant testified that Curtis’ family had become increasingly concerned by his behavior.

Grant said Curtis’ ex-wife told authorities that he fought with his daughter around Christmas and told her, “Maybe I should go ahead and kill you.”

Madison Curtis said after the hearing that she loves her father and stands by him.

Grant also testified that Curtis’ ex-wife said Curtis once told her that he was in hostage situation in Chicago after a breaking up with a former girlfriend, threatened suicide and shot a gun in the air.

However, the agent said they haven’t been able to find a record of that.

Grant’s testimony ended Friday evening, but the hearing is set to continue Monday morning.

In court documents, Curtis’ attorney, Christi McCoy, gave some details of Curtis’ arrest. Curtis had gone to get his mail outside his home and was planning to go to his ex-wife’s home to cook dinner for her and their children when he was approached by officers in SWAT gear, she wrote. He was then interrogated at an FBI office for several hours, handcuffed and chained to a chair.

Curtis cooperated to the best of his ability, but when he suggested he might need a lawyer, an agent discouraged that, McCoy wrote.

According to an FBI affidavit, the letters he sent read: “Maybe I have your attention now even if that means someone must die.”

Officials have confirmed that the letters contained ricin.

While the toxin can be extremely lethal in its purest form, experts say more crude forms are relatively easy to make.

The FBI has not yet revealed details about how the ricin was made or how lethal it may have been. It was in a powdered form inside the envelopes, but the FBI said no one has been sickened by it so far. A senate official said Thursday that the ricin was not weaponized, meaning it wasn’t in a form that could easily enter the body.

More than a dozen officials, some wearing hazardous materials suits, were searching the home Friday where Curtis was arrested in Corinth, Miss. FBI spokeswoman Deborah Madden would not say if authorities have found ricin or materials used to make it in Curtis’ home, and officials have not provided details about how Curtis may have either obtained or made the ricin.

Curtis’ ex-wife has said he likely didn’t have the know-how to make ricin, and she did not know where he would buy it because he was on disability.

But ricin was once known as “the poor man’s bioterrorism” because the seeds are easy to obtain and the extraction process is relatively simple, said Murray Cohen, the founder of the Atlanta-based Frontline Foundation, which trains workers on preparedness and response to bioterrorism and epidemics.

“Any kid that made it through high school science lab is more than equipped to successfully make a poison out of this stuff. Any fool can get recipes off the Internet and figure out how to do it,” Cohen said.

Those seeds, which look a bit like coffee beans, are easy to buy online and are grown around the world; they are often used to make medicinal castor oil, among other things. However, using the seeds to make a highly concentrated form of ricin would require laboratory equipment and expertise to extract, said Raymond Zilinskas, a chemical and biological weapons expert.